Predrag was a Serbian fighter in the Sarajevo neighborhood of Grbavica. Everyone called him by his nickname, "Gaga." On the eve of his 36th birthday, May 24, 1993, Gaga stopped to visit an elderly Muslim woman in her apartment. He planned to leave the war zone the next day to visit his ailing brother, who was battling leukemia in Belgrade, Serbia. Gaga never made it out of the woman's apartment alive.

The Muslim was never arrested. The gun disappeared. The Serb army called it a suicide. Some of Gaga's friends whispered a different theory: Gaga had been killed by fellow Serbs for aiding Muslims in his neighborhood.

I spent three years attempting to find out what happened to Gaga during the Bosnian war, what role he played in the butchery, why and how he died. I wanted to find Gaga's killer. I also hoped to grasp why ordinary Serbs fought against their neighbors and former friends in a city I had known for ten years.

The Gaga I knew possessed a compassionate, easy spirit. He was a mountain climber and amateur photographer. I assumed he remained essentially the same during the war.

After my long investigation, a new image of Gaga emerged like a print in his photographer's developing tray. It was my friend's face, but it wore an expression I did not recognize.